The present invention generally relates to transmission control protocol (TCP) data handling, and more particularly to TCP data handling during periods of potential network or operating system downtime.
For users running business critical workloads, e.g., on a network system, such as AIX Power System, it may be desirable to eliminate downtime associated with the deployment of patches or updates to the system running the workloads, e.g., when patches or updates require a reboot of an AIX logical partition. It may be desirable that the patches take effect without any downtime to the running workloads or that the workloads take advantage of new types of patches (e.g., directed to kernel, kernel extensions, libraries). For example, a live kernel update may limit such downtime, but such patches may be limited to kernel and kernel extensions. These patches are typically delivered to users as “iFIXES” and may be in response to user-reported issues. However, some patches may still require an AIX partition reboot, e.g., when a change in the AIX kernel or loaded kernel extensions is required. In some instances, patches to critical libraries may also require an AIX partition reboot.
During a live kernel update, network traffic to and from a logical partition (on a system or node receiving the update) may be blocked. Remote peers in the network (e.g., peer nodes) may transmit data that may not be received by the blocked node, and the remote peers may retransmit the unreceived data. If the time allotted for retransmission (e.g., a retransmit span) is shorter than the duration of the network traffic blockage (e.g., network blackout period), a connection reset may occur.